【正文】 很多：從溶液的配制等基本實驗操作到大型精密儀器的操作。 in a gas collection bottle filled either with mercury or a saturated salt solution.Reaction of 1,4dibromobutane with, various metals. To a refluxing mixture of 2 g. of the appropriate metal and 20 ml of solvent was slowly added g. ( mole) of 1,4dibromobutane. The mixture was usually allowed to reflux overnight. The evolved gases were then measured and analyzed according to the above procedure. The metals, solvents, and reaction products are tabulated in Table I.Reaction of 1,4dibromobutane with methylmagnesium bromide and cobaltous bromide in various solvents. To a refluxing mixture of g. ( mole) of 1,4dibromobutane and 2 g. of cobaltous bromide in 20 ml. of solvent, was added ca. mole of methylmagnesium bromide in the same solvent. The solvents used were ethyl ether, butyl ether, and xylene. In the latter two solvents, the addition reagent was formed by mixing the solvent with the appropriate amount of methylmagnesium bromide in ethyl ether and then removing as much of the ethyl ether as possible by evacuating to water pump pressure. In xylene and butyl ether, the Grignard reagent was added in the form of a slurry. The gases produced were collected and analyzed as described previously.Reactions of nbutyl bromide. (a) A mixture of g. of nbutyl bromide ( mole), g. of cobaltous bromide ( mole), and 1 g. of magnesium was refluxed in 15 ml. of ethyl ether for three hours. The reaction gas was collected and analyzed as before. The results are recorded in Table II.(b) To a refluxing mixture of g. of nbutyl bromide and 1 g. of cobaltous bromide in 15 ml. of ethyl ether was slowly added 25 ml. of ca. 1M rnethylmagnesium bromide. The yield of gas was quantitative based on the amount of methylmagnesium bromide. The analytical results are given in Table II.Reaction of 4phenoxybutyl bromide with magnesium and cobaltous bromide. 4Phenoxybutyl bromide was prepared by the method of Kharasch, et al.。對該反應(yīng)生成的混合物的分析是通過氣相色層分析法來完成的（圖1）。關(guān)于活潑基團置換反應(yīng)的實驗證據(jù)已經(jīng)被斯特西總結(jié)過了。雖然這種異構(gòu)化反應(yīng)在較低溫度下進行時有這樣一種可能性，不過很然有一種可能即在反應(yīng)釜中于丁醚和二甲苯回流下，1—丁烯有足夠長的停留時間來進行如此一個重排反應(yīng)。每種化合物的摩爾百分數(shù)是通過下面的式子計算而來：儀器：帶有地液漏斗和冷凝裝置的100mL三口燒瓶，磁力攪拌器，氣體收集裝置。4—苯氧基丁基溴由卡?瑞斯克法制備。在二甲苯和丁醚中，格式試劑是通過一以漿狀的形態(tài)加入，產(chǎn)生氣體的收集和分析方式如前所述。氣體催化方法。他們提出的關(guān)于正丁基自由基通過氫原子的遷移而生成2—丁基自由基的重排反應(yīng)沒有能夠得到實驗的進一步支持。這系類反應(yīng)的結(jié)果也別列在了表 1 中，在較低溫度的乙醚溶液中回流時，沒有環(huán)丁烷生成——這是對卡森和韋[3]實驗結(jié)果觀察的一個意想不到的結(jié)果。盡管他們沒有能夠提出該反應(yīng)的機理，然而通過對環(huán)丁烷在較少的苯沸騰溶液中生成過程的進一步觀察解釋了該過程是一個反應(yīng)活性較高的反應(yīng)。 the other product being propane. Small amount is abbreviated . b In addition, 53% ethane and 4% propane were found. C No yield of reaction products was measured here due to the large dilution by methane.The experimental results of this study support the view that the metal dehalogenation reactions of 1,4dibromobutane are free radical in nature. However, it should be born in mind that in any reactions as plex as these there is no difficulty in finding explanations of the experimental facts, but only in defending a preferred explanation selected from many. One reasonable reaction scheme which will acmodate the above observations is as follows:In the same fashion the 4bromolbutene (Equation 4) may depose to form 1,3butadiene and 1butene. The 4bromolbutyl radical (A) may be generated either by the direct abstraction of the halogen by the metal or by the thermal deposition of a metal alkyl intermediate.[8]The formation of cyclobutane as envisioned in Equation 2 above is a displacement of bromine atom from carbon by an attacking radical. The experimental evidence regarding radical displacement reactions has been summarized by The formation of a 1,4butyl diradical as suggested by Bawn and Milstead[2] is also a possibility. In order to test the proposal of the 4bromolbutyl radical (A) as:reaction intermediate, the deposition of 4phenoxybutyl bromide with magnesium and tobaltous bromide in refluxing xylene tv as carried out. Again a plex mixture of gaseous products was formed (Table II). Analysis of this mixture showed the same products as observed in the reactions of 1, was formed to the extent of 2 mole percent. Kharasch, Stampa, and Xudenburg[l0] have reported that treatment of 4phenoxybutyl bromide with phenylmagnesium bromide and cobaltous bromide in ether gave predominantly butyl phenyl ether and butenyl phenyl ether. TABLE IIREACTIONS OF nBUTYL BROMIDE AND 4PHENOXYBUTYL BROMIDEReagentSolventYield,Ml.Products, Mole%C2H4C4H101—C4H8 nButyl bromide, moleMg+CoBr2Et2O49005521CH3MgBr+CoBr2Et2O…a611204Phenoxybutyl bromide, .0052 moleMg+CoBr2Xylene255379ReagentSolventYield,Ml.Products, Mole%2—C4H81,3—C4H6Cyclo C4H8Mg+CoBr2Et2O49024……CH3MgBr+CoBr2Et2O…a………Mg+CoBr2Xylene251012 a No yield of reaction products was measured due to the high dilution with methane. The other major product (63%) was pentane.Both trans and cis 2butene (the ratio trans/cis varied from two to five) were formed in each of the reactions , Lambert, and Urry[11] noted the formation of 2butene when 1chloro3phenylpropane was treated with butylmagnesium bromide and cobaltous bromide. Their suggestion of the rearrangement of a nbutyl radical to a secbutyl radical via a hydrogen atom migration has not received further experimental support. However,should such a migration occur then the formation of 2butene may be postulated as follows:When butyl bromide is allowed to react with nagnesium and cobaltous bromide in ether, the yields of 1butene and 2butene were essentially the same (Table II). In another experiment butyl bromide and cobaltous bromide were allowed to react with methylmagnesium bromide. There vas no observable yield in 2butene under these conditions (Table II) and the high yield of pentane suggests that the rebination of methyl and butyl radic